Machine for grinding lenses.



. 110.772,431. y* PATENTED 001218', 1904.

' c. L. RAMEAU.

MACHINE POR GRINDING LENSES.

` APPLIOATION FILED nu ze. 190s. No MODEL.4 a slums-SHEET 2.

No. 772,431. PATBNTEDOGT. is, 1904.

. .0. L. YMmmm.

MACHINE POR GRINDING LBNsBs.

, APPLIUATION FILED In '26. 1903.

NO MODEL. 3 BRIEFS-SHEET 3.

. i l /IZ f@ 'nfroHA/EXS ,Patented October 18, 1904.

- UNITED A"STATES PATENT OFFICE.

`CLAUDE LOUIS RAMEAU, OF PARIS, FRANCE.

MACHINE vForaela'naolnle LENSES.

SPECIFICATION forminglpart of Letters Patent No. 772,431, dated OctoberI8, 1904. .ippncason ined May 26,1903. serial No. 158,870. (No model.) 1

To a/ZZ whom tm/(ry concern:

Be it known that I, OLAUDELOUIS RAMEAU, civil engineer, a citizen of the`Republic of France, and a resident of No. 11() Rue dAngoulme, Paris, inthe Republic of France, have invented certain new and usefulImprovements vin Machines for Grinding Lenses, of which the following isaspeciiication.

This invention relates toimprovements in machines for grinding' lenses.

Machines for grindinglens-surfaces gener- 'ally1 consist of two disks,either plain, convex,

or concave, the lower disk being fixed or adapted to turn very slowlyabout its axis and the upper one movable, with its center usuallydescribing a circle around the axisof the lower disk. In this movementthe grinding material, such as pulp or dust, is constantly thrown towardthe circumference and the grinding of the lens-surface is effectedin anunequal and irregular manner. It would therefore be a great advantage tocause the center of one of the disks to describe round the fixed axisofthe other disk a curve, so that the grinding material after being throwntoward the circumference would bebrought back toward va completeelongated and closed epicycloid.

Fig. 3 is a vertical sectional View of the device employed for producingthe epicycloidal movement of one of the disks. Fig. 4 is a horizontalsectional view through line A B of Fig. 3. Figs. 5A and Gare detail planviews of the device illustrated in Fig. 3. Fig. 7 is a whole elevationview of a model of construction of the new machine. Fig. 8 is a planview'of same." p

It is known that the epicycloid is the curve generated by a point of amovable circle which rolls without sliding on a steady circle. If thecircle B C rolls on the circle O A, Fig. l,

each point of the circle B O will describe an ep'icycloid.v If the pointconsidered is on the circumference of -the circle B C, the curvev 1 ornormal epicycloid will be obtained. If the point .is inside thecircumference, a shortened epicycloid will be obtained, of which thecircle 2 described bythe center B isa special case. Finally,- if thepoint is taken out of the generating circumference, as at D, for`instance, the buckled curve 3 or ,elongated epicycloid will be formed.Fig. 2 shows this. elongated epicycloid entire and closed after asuitable number of revolutions. kIt is mainly thispath that one willseek to impart to the grindingdisk during'the working of themachine.

Themachine comprises a standard a, supporting the different parts, adriving-shaft b, a vertical shaft c, on the upper end of which Yissecured the lower disk d, and a second vertical shaft e, which carriesthe upper disk f by means of ajoint hereinafter described. The

lens-surfaces to betreated and the grinding material are placed,asusual,betweenthe disks Z and j'. `The first vertical shaft c is given aslow rotary movement from the driving-shaft v through suitablegear---for instance,'a pair of toothed wheels g and 7L, a worm c',mounted on the shaft j', and a worm-wheel Z6, secured to the verticalshaft c and gearing with the worm The shaft e receives a rotary movementfrom the driving-shaft Z2 through suitablepulleys Z'm n and a belt p.This shaft e carries a head q, resting on balls r, rolling in annularraces in a part fixed to the frame.

The said shaft is prolonged below the head q and carries a pinion s,gearing with another pinion t. These two pinions, of which the number ofteeth are prime one to each other,

.are mounted in a hoop or'frame u, which is end a horizontal plate e,having three parallel slots or recesses 5, into which engage bolts orpins 6,iiXed to a tube or sleeve 7. This sleeve carries the shaft 8,which drives the upper grinding disk. An elastic connectionformed, forinstance, by a helical spring 9- maybe interposed between the plate andthe shaft which moves it. Owing to the grooves in the plate z and thesaid fasteningbolts the shaft 8 of the sleeve can be made to coincidewith the shaft y of the plate a or be moved therefrom. By these means itis possible for any point on the grinding-disk to describe a normal,elongated, or shortened epicycloid.

Having now described my invention, what I claim as new,and desire tosecure by Letters Patent, is-

1. A machine for grinding lens surfaces comprising a lowergrinding-disk, a second grinding-disk above the same, a vertical shaft,

a frame rotatively carried thereby, a connection from said frame to theupper disk` means for rotating said connection and means for rotatingthe shaft, substantially as described.

2. A machine for grinding lens-surfaces comprising a lowergrinding-disk, means for rotating said disk, a second disk above thefirst, a vertical shaft e, aframe rotatably7 carried thereby, a shaft ycarried by said frame,

a shaft Scarrying the upper grinding-disk and an adjustable connectionbetween shaft y and shaft 8 and means for rotating shaft e,substantially as described.

3. A machine for grinding lens surfaces comprising a grinding-disk (Zsecured on the upper end of a vertical shaft c, means for causing saidshaft c to turn, a second grindingdisk f arranged above the first one, avertical shaft 8 pivotcd centrally on the top of the disk f, a sleeve 7in which is arranged the shaft 8,a plate provided with parallel grooves5, bolts 6 engaged in said grooves and securing the sleeve to the platein the proper position, a vertical round shaft ,1/ fixed on the uppersurface of the plate .2', a pinion mounted on the shaft g//, a verticaldriving-shaft e arranged parallel to thc shaft 1/ and guided in theframe, a pinion s mounted on the shaft e and gearing with pinion f', ahead r] integral with the shaft e and resting on balls carried by theframe of the machine, a hoop or frame u fixed to the shaft e and looselypassed over the shaft z/, and means for causing the shaft e to turn,substantially as and for the purpose set forth.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

CLAUDE LOUIS RAMEAU.

fitnessesz ANTOINE HAvoIX, AUGUSTUS E. INGRAM.

